A semiconductor wafer (workpiece) in which a circuit pattern is formed is diced into semiconductor chips (chip-shaped workpiece) (a dicing step) after the thickness thereof is adjusted as necessary by backside polishing. In the dicing step, the semiconductor wafer is generally washed with an appropriate liquid pressure (normally, about 2 kg/cm2) in order to remove a cutting layer. The semiconductor chip is then fixed onto an adherend such as a lead frame with an adhesive (a mounting step), and then transferred to a bonding step. In the mounting step, the adhesive has been applied onto the lead frame or the semiconductor chip. However, with this method, it is difficult to make the adhesive layer uniform and a special apparatus and a long period of time become necessary in the application of the adhesive. For this reason, a dicing die-bonding film is proposed that adhesively holds the semiconductor wafer in the dicing step and also imparts an adhesive layer for fixing a chip that is necessary in the mounting step (for example, see Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No. 60-57642).
The dicing die-bonding film described in Patent Document 1 is composed of an adhesive layer that is formed on a supporting base material so that it can be peeled. That is, the dicing die-bonding film is made so that after the semiconductor wafer is diced while being held by the adhesive layer, the semiconductor chip is peeled together with the adhesive layer by stretching the supporting base material, the semiconductor chips are individually recovered, and then they are fixed onto an adherend such as a lead frame with the adhesive layer interposed therebetween.
Good holding power toward the semiconductor wafer so that a dicing failure, a dimensional error, etc. do not occur and good peelability in which the semiconductor chip after dicing can be peeled from the supporting base material integrally with the adhesive layer are desired for the adhesive layer of this type of the dicing die-bonding film. However, it has been by no means easy to balance both these characteristics. Particularly, when a large holding power is required for the adhesive layer such as in the method of dicing the semiconductor wafer with a rotary round blade, it has been difficult to obtain a dicing die-bonding film that satisfies the above characteristics.
Therefore, in order to overcome such problems, various improvement methods have been proposed (for example, see Patent Document 2). In Patent Document 2, a method of interposing a pressure sensitive adhesive layer that can be cured by ultraviolet rays between the supporting base material and the adhesive layer, decreasing the adhering force between the pressure sensitive adhesive layer and the adhesive layer by curing this with ultraviolet rays after dicing, and facilitating picking up the semiconductor chip by peeling both layers is proposed.
However, there is the case where a dicing die-bonding film that is excellent in balance between retention upon dicing and releasability after dicing is hardly obtained even by this modified method. For example, when a large semiconductor chip measuring 10 mm×10 mm or more or a very thin semiconductor chip measuring 25 to 75 μm in thickness is to be obtained, it is not easy to pick up the semiconductor chip using a common die bonder.
To solve this problem, Patent Document 3 described below discloses that an attempt is made to improve pickup properties by irradiating the portion corresponding to the semiconductor wafer attaching portion with ultraviolet rays in a pressure-sensitive adhesive layer thereby curing the portion. However, in the dicing die-bonding film described in Patent Document 3, there is the case where adhesive residue of an adhesive constituting a die-bonding film generates in a cut surface after dicing and thus cut surfaces are reattached to each other (blocking), resulting in a problem that it becomes difficult to pick up a semiconductor chip.    Patent Document 1: JP-A 60-57642    Patent Document 2: JP-A 2-248064    Patent Document 3: JP-A 2005-5355